1. Field of the Invention
The present invention relates to an electronic timepiece provided with a wireless communication section.
2. Description of Related Art
A timepiece has been developed which is equipped with a wireless communication function such as Bluetooth (registered trademark) and is able to have wireless communication with a mobile phone and the like.
Also, an electronic timepiece is typically provided with an illumination device for illuminating a display section or outside and the illumination device is driven by pushing an illumination button.
Further, as a related art of the invention of this application, Japanese Patent Application Laid-Open Publication No. 2006-197510 (corresponding to US 2006/0160488 A1) disclosed a technique in an apparatus which conducts near field wireless communication to drive a light-emitting diode so as to flash during the communication to notify outside that the apparatus is currently conducting the communication.
In an electronic timepiece driven by a small battery, a response performance of a power source with respect to a large load is relatively low. Therefore, when there is a plurality of operations each consuming a large current, it is necessary to prevent such operations from being carried out simultaneously. For instance, transmitting/receiving a wireless signal and driving an illumination device are operations each requiring a large amount of current, and it is necessary to prevent these operations from being carried out at the same time.
Given such situation, the inventor of this invention has conducted studies on a control when wireless communication and illumination driving are carried out in the same period. This control is for stopping driving of an illumination device in a very short period, in which a radio frequency (RF) circuit is activated and a wireless signal is actually transmitted/received, during a wireless communication period. During the communication period, an actual transmission/receipt period of a wireless signal is as short as, for example, 3 millisecond (ms) per second, so it was expected that stopping driving of the illumination device during the transmission/receipt period does not cause a problem.
However, it was found that a human senses with eyes a light-off period as light flicker, even in the case that the period is 3 ms and would not be recognized as blinking by human eyes if the period occurs in a very short cycle, when this very short light-off period occurs in a relatively long cycle during continuous lighting of the illumination device.
This means that, when wireless communication and illumination driving are carried out in the same period, if a control for stopping driving of the illumination device is carried out only for a very short period in which the RF circuit is activated and a wireless signal is actually transmitted/received during the communication period, a user senses illumination flicker occurring in a relatively long cycle, and such illumination flicker brings discomfort to the user.
The present invention provides an electronic timepiece which can avoid illumination flicker bringing discomfort to a user, even when performing a control for preventing large loads from overlapping when wireless communication and illumination driving are carried out in the same period.